+ mm-vmscan-guarantee-drop_slab_node-termination-fix.patch added to -mm tree

[akpm@linux-foundation.org]

The patch titled
     Subject: mm, vmscan: guarantee drop_slab_node() termination-fix
has been added to the -mm tree.  Its filename is
     mm-vmscan-guarantee-drop_slab_node-termination-fix.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-vmscan-guarantee-drop_slab_node-termination-fix.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-vmscan-guarantee-drop_slab_node-termination-fix.patch

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------------------------------------------------------
From: Vlastimil Babka <vbabka@suse.cz>
Subject: mm, vmscan: guarantee drop_slab_node() termination-fix

Matthew reports [1] that if we free enough objects, we can eventually
right-shift by BITS_PER_LONG, which is undefined behavior.  Raise the
threshold from 0 to 1 which means we will shift only up to
BITS_PER_LONG-1.

[1] https://lore.kernel.org/linux-mm/YSTDnqKgQLvziyQI@casper.infradead.org/

Link: https://lkml.kernel.org/r/2f034e6f-a753-550a-f374-e4e23899d3d5@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/vmscan.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/vmscan.c~mm-vmscan-guarantee-drop_slab_node-termination-fix
+++ a/mm/vmscan.c
@@ -952,7 +952,7 @@ void drop_slab_node(int nid)
 		do {
 			freed += shrink_slab(GFP_KERNEL, nid, memcg, 0);
 		} while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL);
-	} while ((freed >> shift++) > 0);
+	} while ((freed >> shift++) > 1);
 }
 
 void drop_slab(void)
_

Patches currently in -mm which might be from vbabka@suse.cz are

mm-slub-dont-call-flush_all-from-slab_debug_trace_open.patch
mm-slub-allocate-private-object-map-for-debugfs-listings.patch
mm-slub-allocate-private-object-map-for-validate_slab_cache.patch
mm-slub-dont-disable-irq-for-debug_check_no_locks_freed.patch
mm-slub-remove-redundant-unfreeze_partials-from-put_cpu_partial.patch
mm-slub-unify-cmpxchg_double_slab-and-__cmpxchg_double_slab.patch
mm-slub-extract-get_partial-from-new_slab_objects.patch
mm-slub-dissolve-new_slab_objects-into-___slab_alloc.patch
mm-slub-return-slab-page-from-get_partial-and-set-c-page-afterwards.patch
mm-slub-restructure-new-page-checks-in-___slab_alloc.patch
mm-slub-simplify-kmem_cache_cpu-and-tid-setup.patch
mm-slub-move-disabling-enabling-irqs-to-___slab_alloc.patch
mm-slub-do-initial-checks-in-___slab_alloc-with-irqs-enabled.patch
mm-slub-do-initial-checks-in-___slab_alloc-with-irqs-enabled-fix.patch
mm-slub-do-initial-checks-in-___slab_alloc-with-irqs-enabled-fix-fix.patch
mm-slub-move-disabling-irqs-closer-to-get_partial-in-___slab_alloc.patch
mm-slub-restore-irqs-around-calling-new_slab.patch
mm-slub-validate-slab-from-partial-list-or-page-allocator-before-making-it-cpu-slab.patch
mm-slub-check-new-pages-with-restored-irqs.patch
mm-slub-stop-disabling-irqs-around-get_partial.patch
mm-slub-move-reset-of-c-page-and-freelist-out-of-deactivate_slab.patch
mm-slub-make-locking-in-deactivate_slab-irq-safe.patch
mm-slub-call-deactivate_slab-without-disabling-irqs.patch
mm-slub-move-irq-control-into-unfreeze_partials.patch
mm-slub-discard-slabs-in-unfreeze_partials-without-irqs-disabled.patch
mm-slub-detach-whole-partial-list-at-once-in-unfreeze_partials.patch
mm-slub-separate-detaching-of-partial-list-in-unfreeze_partials-from-unfreezing.patch
mm-slub-only-disable-irq-with-spin_lock-in-__unfreeze_partials.patch
mm-slub-dont-disable-irqs-in-slub_cpu_dead.patch
mm-slab-make-flush_slab-possible-to-call-with-irqs-enabled.patch
mm-slub-move-flush_cpu_slab-invocations-__free_slab-invocations-out-of-irq-context-fix.patch
mm-slub-move-flush_cpu_slab-invocations-__free_slab-invocations-out-of-irq-context-fix-2.patch
mm-slub-optionally-save-restore-irqs-in-slab_lock.patch
mm-slub-make-slab_lock-disable-irqs-with-preempt_rt.patch
mm-slub-protect-put_cpu_partial-with-disabled-irqs-instead-of-cmpxchg.patch
mm-slub-use-migrate_disable-on-preempt_rt.patch
mm-slub-convert-kmem_cpu_slab-protection-to-local_lock.patch
mm-slub-convert-kmem_cpu_slab-protection-to-local_lock-fix.patch
mm-slub-convert-kmem_cpu_slab-protection-to-local_lock-fix-2.patch
mm-vmscan-guarantee-drop_slab_node-termination.patch
mm-vmscan-guarantee-drop_slab_node-termination-fix.patch